MPs are set to vote on a series of options to choose a way forward for the UK's departure from the European Union.
Monday evening's indicative votes will give MPs the opportunity to say what they think the Government should do next with Brexit, however, the Prime Minister has previously said she does not have to follow the outcome of any of the votes.
A series of indicative votes were held last week, but they came to no conclusion, with MPs voting down every option put before them.
For Monday's votes, Labour and the SNP have said they will whip MPs to vote for Common Market 2.0.
Whilst many MPs could rebel against the plan, it could also get a deal across the line.
But what is Common Market 2.0 and what could it mean for the UK's future with the European Union after Brexit?
Why is it called Common Market 2.0?
If MPs vote for Commons Market 2.0 on Monday night, they are voting not for something new, but something old.
The plan takes its name from the fact that Britain essentially joined Common Market 1.0 in 1973 - originally set up in the 1950s by France, West Germany, Italy, the Netherlands, Belgium and Luxembourg.
The Common Market was the precursor to the European Union - originally just an economic project, which later evolved to become a political one too.
What is it?
Common Market 2.0 envisages Britain joining the European Free Trade Association (EFTA), which is effectively a sister organisation of the EU.
Norway, Iceland and Lichtenstein are also members, enjoying a close relationship with the EU without actually being a member.
Together with the 28 EU states, they all form the European Economic Area.
In practice, the plan would involve:
Being part of the EU's single market, like we are now
Contributing to EU budgets, but less than we do now
Following many EU laws and regulations, but with significantly less influence over them
Accepting freedom of movement (immigration), although supporters argue we could negotiate opt-outs
Leaving the Common Agricultural Policy and Common Fisheries Policy
No longer electing MEPs or sending commissioners to Brussels
No longer being ruled by the European Court of Justice
Unlike other members of EFTA, Common Market 2.0 also envisages Britain being a member of a customs arrangement with the EU, closely mirroring the customs union, to allow trade to flow freely and avoid a hard border between Northern Ireland and the Republic of Ireland.
Who is supporting it?
The plan was conceived by the Conservative MP Nick Boles and the Labour MP Lucy Powell, but has now secured cross-party support.
Both Labour and the SNP will ask their MPs to vote for it on Monday - a significant development.
Add to that the 37 Conservative MPs who backed the plan last time, plus potentially a few more this time around, and there may be a majority for it.
Northern Ireland's DUP have said they will abstain.
Could it work?
The EU has expressed some scepticism about the plan.
Currently, EFTA members aren't allowed to be in a customs union with the EU, and Common Market 2.0 envisages Britain enjoying all the advantages of EU membership while cherry picking the bits it doesn't like.
No EFTA member has managed to negotiate the scale of opt-outs Britain would be demanding.
So why does it matter?
Regardless of whether the plan could be negotiated with the EU, it may affect negotiations closer to home.
If MPs do indeed back the plan, it could put pressure on Brexit-supporting Conservatives who've so far refused to vote for the Prime Minister's deal.
Theresa May could put Common Market 2.0, or any other version of Brexit MPs opt for, to a head-to-head vote with her own deal later this week.
Her version of Brexit would be the hardest on offer - what would MPs do then?
For now though, several rebels are digging in deep.
Downing Street won't decide its next move until MPs have made theirs, which should be revealed after 10pm on Monday night.